botan: Add Botan plugin to libstrongswan

src/libstrongswan/plugins/botan/botan_diffie_hellman.c

@@ -0,0 +1,261 @@
+/*
+ * Copyright (C) 2018 René Korthaus
+ * Copyright (C) 2018 Konstantinos Kolelis
+ * Rohde & Schwarz Cybersecurity GmbH
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "botan_diffie_hellman.h"
+
+#include <botan/build.h>
+
+#ifdef BOTAN_HAS_DIFFIE_HELLMAN
+
+#include "botan_util.h"
+
+#include <botan/ffi.h>
+
+#include <utils/debug.h>
+
+typedef struct private_botan_diffie_hellman_t private_botan_diffie_hellman_t;
+
+/**
+ * Private data of an botan_diffie_hellman_t object.
+ */
+struct private_botan_diffie_hellman_t {
+
+	/**
+	 * Public botan_diffie_hellman_t interface
+	 */
+	botan_diffie_hellman_t public;
+
+	/**
+	 * Diffie Hellman group number
+	 */
+	diffie_hellman_group_t group;
+
+	/**
+	 * Private key
+	 */
+	botan_privkey_t dh_key;
+
+	/**
+	 * Diffie hellman shared secret
+	 */
+	chunk_t shared_secret;
+
+	/**
+	 * Generator value
+	 */
+	botan_mp_t g;
+
+	/**
+	 * Modulus
+	 */
+	botan_mp_t p;
+
+};
+
+bool load_private_key(private_botan_diffie_hellman_t *this, chunk_t value)
+{
+	botan_mp_t xa;
+	if (chunk_to_botan_mp(value, &xa))
+	{
+		return FALSE;
+	}
+
+	if (botan_privkey_destroy(this->dh_key) ||
+		botan_privkey_load_dh (&this->dh_key, this->p, this->g, xa))
+	{
+		return FALSE;
+	}
+	return TRUE;
+}
+
+METHOD(diffie_hellman_t, set_other_public_value, bool,
+	private_botan_diffie_hellman_t *this, chunk_t value)
+{
+	botan_pk_op_ka_t op;
+
+	if (!diffie_hellman_verify_value(this->group, value))
+	{
+		return FALSE;
+	}
+
+	chunk_clear(&this->shared_secret);
+	botan_pk_op_key_agreement_create(&op, this->dh_key, "Raw", 0);
+
+	/* get shared secret key size */
+	if (botan_pk_op_key_agreement(op, NULL, &this->shared_secret.len, value.ptr,
+	                              value.len, NULL, 0)
+	    != BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE)
+	{
+		return FALSE;
+	}
+
+	this->shared_secret = chunk_alloc(this->shared_secret.len);
+	if (botan_pk_op_key_agreement(op, this->shared_secret.ptr,
+	                              &this->shared_secret.len, value.ptr,
+	                              value.len, NULL, 0))
+	{
+		return FALSE;
+	}
+
+	return TRUE;
+}
+
+METHOD(diffie_hellman_t, get_my_public_value, bool,
+	private_botan_diffie_hellman_t *this, chunk_t *value)
+{
+	*value = chunk_empty;
+
+	/* get key size of public key first */
+	if (botan_pk_op_key_agreement_export_public(this->dh_key, NULL, &value->len)
+	    != BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE)
+	{
+		return FALSE;
+	}
+
+	*value = chunk_alloc(value->len);
+	if (botan_pk_op_key_agreement_export_public(this->dh_key, value->ptr,
+	                                            &value->len))
+	{
+		chunk_clear(value);
+		return FALSE;
+	}
+
+	return TRUE;
+}
+
+METHOD(diffie_hellman_t, set_private_value, bool,
+	private_botan_diffie_hellman_t *this, chunk_t value)
+{
+	return load_private_key(this, value);
+}
+
+METHOD(diffie_hellman_t, get_shared_secret, bool,
+	private_botan_diffie_hellman_t *this, chunk_t *secret)
+{
+	if (this->shared_secret.len == 0)
+	{
+		return FALSE;
+	}
+
+	*secret = chunk_clone(this->shared_secret);
+	return TRUE;
+}
+
+METHOD(diffie_hellman_t, get_dh_group, diffie_hellman_group_t,
+	private_botan_diffie_hellman_t *this)
+{
+	return this->group;
+}
+
+METHOD(diffie_hellman_t, destroy, void,
+	private_botan_diffie_hellman_t *this)
+{
+	botan_mp_destroy(this->p);
+	botan_mp_destroy(this->g);
+	botan_privkey_destroy(this->dh_key);
+	chunk_clear(&this->shared_secret);
+	free(this);
+}
+
+/*
+ * Generic internal constructor
+ */
+botan_diffie_hellman_t *create_generic(diffie_hellman_group_t group,
+							chunk_t g, chunk_t p)
+{
+	private_botan_diffie_hellman_t *this;
+
+	INIT(this,
+		.public = {
+			.dh = {
+				.get_shared_secret = _get_shared_secret,
+				.set_other_public_value = _set_other_public_value,
+				.get_my_public_value = _get_my_public_value,
+				.set_private_value = _set_private_value,
+				.get_dh_group = _get_dh_group,
+				.destroy = _destroy,
+			},
+		},
+		.group = group,
+	);
+
+	if (chunk_to_botan_mp(p, &this->p))
+	{
+		destroy(this);
+		return NULL;
+	}
+
+	if (chunk_to_botan_mp(g, &this->g))
+	{
+		destroy(this);
+		return NULL;
+	}
+
+	chunk_t random;
+	rng_t *rng;
+	rng = lib->crypto->create_rng(lib->crypto, RNG_STRONG);
+	if (rng && rng->allocate_bytes(rng, p.len, &random))
+	{
+		rng->destroy(rng);
+		if (!load_private_key(this, random))
+		{
+			destroy(this);
+			chunk_clear(&random);
+			return NULL;
+		}
+	}
+
+	return &this->public;
+}
+
+/*
+ * Described in header.
+ */
+botan_diffie_hellman_t *
+botan_diffie_hellman_create(diffie_hellman_group_t group)
+{
+	diffie_hellman_params_t *params;
+	params = diffie_hellman_get_params(group);
+	if (!params)
+	{
+		return NULL;
+	}
+	return create_generic(group, params->generator, params->prime);
+}
+
+/*
+ * Described in header.
+ */
+botan_diffie_hellman_t *
+botan_diffie_hellman_create_custom(diffie_hellman_group_t group, chunk_t g,
+								   chunk_t p)
+{
+	if (group == MODP_CUSTOM)
+	{
+		return create_generic(group, g, p);
+	}
+	return NULL;
+}
+
+#endif